Snellville is a bit outside the heat island, but I recommend Citrangequats, Ichang lemons, or Changshas on the South side of property.If you only have an exposed spot, a Dunstan Citrumelo or Morton Citrange should work.

If you are willing to use containers, plant anything you want, but Meyer Lemons and Satsumas will need less nights of protection.

Just temper your expectations about taste. You should probably taste a few before you plant them....

I have Dunstan citrumelo unprotected that have survived the past two years. I think they make a decent version of a sour grapefruit. Note: it is a novelty tree to grow in cold climate without winter protection, not a store-quality fruit. It is better, more ornamental and noteworthy with larger more impressive fruit and leaves than poncirus trifoliata.

I have Croxton but I cover mine in winter and protect from severe freeze with space heater. Croxton comes from Columbia, SC which I believe is zone 8a and grows at Mckinzie Farms in Scranton, SC zone 8a, where it is protected with microsprinklers during freezing nights. I protect my grapefruit from freezing largely due to need to overwinter the fruit which takes over a year to mature in my climate. 7b you probably have hot summers so your grapefruit may be ripe enough to eat before the first hard freeze in your area. Croxton is real citrus; 7b I believe is a low of 5 degrees; I've lost citranges at 5 degrees and this past spring lost half of the height from citranges when it got down to only 14 degrees after they started waking up from a warmer winter/spring. You would have to protect Croxton or any other real citrus in 7b.

Changsha Mandarin, keraji Mandarin, bloomsweet. All good fruit, but, probably more of a 8a/b fruit. Need to placed in a very good microclimate and will need protection under 15. Call Stan McKenzie, he has an awesome selection and good quality trees.

PT and its hybrids are better suited to clay soils than regular citrus which like sandier soils. Go to Mckenzie farms.com; Stan Mckenzie has/had copies of the book called "Hardy Citrus for the Southeast ", by Tom McClendon, for sale. You could also try Ben Salley out of Columbia SC, also sells citrus; he's who I got my Croxton from, and he lives across the street from the original Croxton. His business and site on Facebook is called "Simply Citrus". I don't know if you can take citrus into GA from SC though.

No, never. My initial Thomasville was from B.Voss, grafted very low on poncirus. It died after -12C, but I had several of its seedlings, they usually become damaged at approximately -10C. It should be taken into account, that in my climate this sort of temperatures occur during long cold spells with more than one week of frozen ground. Seedlings are coming nicely from roots after complete trunk death. Among them many are weak, having root problems, but one in 10 is growing very quickly and fruiting in 4-5 years. I have already their fourth generation, but hardiness is not improving.

Are seedlings different from their mother or are they just copies ( not in the meaning of clones, but nearly identical)?

Seedlings can be either "zygotic" or "nucellar". Some citrus varieties produce almost entirely nucellar seed, while some produce all zygotic.Nucellar are the ones that are genetic clones (exact copies). Certain citrus varieties tend to produce seedlings that mostly resemble the traits of their parents, even though they are zygotic and may not be exact genetic copies. Typically if an offspring is a direct hybrid between two different species of parents the offspring will be more likely to be unpredictable.

I don't know but I would imagine citrangequat would produce mostly to entirely nucellar seeds, based on the fact that both calamondin (orange x kumquat) and citrange are nucellar. (kumquat is zygotic)

I have already their fourth generation, but hardiness is not improving.

Are seedlings different from their mother or are they just copies ( not in the meaning of clones, but nearly identical)?

Mikkel, Thomasville forms seeds only when cross-pollinated. The seeds contain one or several embryos, but are all nucellar. I germinated hundreds of them, up to now found two, that could eventually turn to be mutants, but not a single hybrid. Many of Thomasville seedlings are weak, having root problems, but it seems that this feature is not hereditary, when grafted they develop nicely.

Hi, new here, though I've spent the past month or so scouring the web for info about hardy citrus. I'm also in 7b and recently acquired an Owari (on trifoliate roots) from Stan McKenzie. Going to put it in the ground, as I have a fairly warm microclimate (urban area, protected from wind, side of a gentle slope, etc), and plan to use a portable greenhouse, Christmas lights, water buckets, etc to even out temp extremes. I've already got a few container citrus and I love experimenting and trying fairly inadvisable things.